1. Field of the Invention
The present invention relates to an image forming method utilized in the field of copy machines, printers, and facsimiles using electric photographs and an electrostatic recording system.
2. Description of Related Art
Conventionally, in electrophotography, the surface of an electrostatic image supporting material (hereinafter, also referred to as a photoreceptor) is uniformly charged and an electrostatic image is formed by exposure to light under a predetermined manuscript information, and a toner is flied on the electrostatic image and thereby a toner image is formed. Then, the toner image is transferred onto a predetermined form, and by heating and pressurizing with a fixing roller, the toner image is fixed and thereby, the image is formed.
The toner used in electrophotography has been obtained by, mixing at least a colorant-containing-thing in a binder resin, then melting-kneading by two-shaft kneading machine and so forth and cooling, and then going through a grinding process and a classification operation, and then adding and mixing an inorganic oxide and so forth therein.
In the grinding process, a shape of the toner to be produced is different by a factor such as a kind of the grinding equipment and so forth. And, it is known that the shape affects the cleaning property or the transfer property. Accordingly, there has been proposed a method that the shape of the toner is set to be in a prescribed range and thereby the cleaning performance and the transferring performance are improved (see, for example, Japanese Patent No. 3,372,698).
On the other hand, in a two-component development system, in order to enhance the transferring performance, it has been investigated to obtain a high-quality and high-definition image by determining density of a magnetic brush formed on a development sleeve and so forth. For example, there has been proposed a method that the magnetic brush of a two-component toner on a development sleeve is contacted with a photoreceptor, and a development bias containing bias for removing fog is applied thereto and the electrostatic latent image on the photoreceptor is developed, and therewith, the post-transfer residual toner on the photoreceptor is removed (see, for example, Japanese Patent No. 3,382,483).
However, as shown in the Japanese Patent No. 3,372,698, when the shape of the toner is merely restricted and set to be small-sized, the content of the toner of 5 μm or less is prone to increase and the liquidity of the toner is prone to lower. Therefore, degradation of the agitation and carrier property in the development equipment or lowering of the toner amount carried on the development sleeve is caused, and concentration failure or fog in an overlaid part is caused, and therefore, it becomes difficult to obtain an image having uniformity in gray or dot reproducibility and quality of the image becomes degraded. Moreover, if the post-transfer residual toner can be removed as described in Japanese Patent No. 3,372,698, a larger toner amount becomes required for obtaining a predetermined image concentration and thereby, the wasted toner such as the post-transfer residual toner becomes larger, and also this is not preferable environmentally.